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Old 05-31-2013, 07:42 PM
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DaveInDenver DaveInDenver is offline
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Join Date: Jun 2006
Location: Larimer County
Posts: 8,408

That chart is probably overly dramatic (and they conveniently sell tranny coolers), but the fundamentals seems true that you don't want the ATF going beyond about 225F.

The thermal expansion coefficient of materials is constant, most aluminums being about 12 to 13 ppm (e.g. microinch) per F and irons are typically about 6 to 7. My main worry would be ruining the fluid more than the marginally worse metal expansion. Joining dissimilar metals is a bad idea but unfortunately common on our junk.
'91 Pickup - Imelda
'08 Tacoma TRD - Donna

"The Only Thing That Is Constant Is Change." -- Heraclitus

Last edited by DaveInDenver; 05-31-2013 at 08:06 PM.
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